Dot 3 vs 4 vs 5.1

[Christopher]

I have a 2002 jeep wrangler tj. It's time to flush the brake fluid on it, and I was wondering what type of brake fluid would be compatible with the stock brake system. I know that dot 4 would be compatible with the current dot 3 system. But could I use dot 5.1 in the system?

Sorry if that was a bit wordy...

 

[CEE DOG]

If you don't have the manual I would google it or call a dealership to discover the recomended fluid.

 

[ScottB]

like all fluids there are many types and each have benefits and weaknesses. You should read the maintenance requirements and met or exceed them. Dont skimp on maintenance or bigger repairs could come.

 

[Christopher]

like all fluids there are many types and each have benefits and weaknesses. You should read the maintenance requirements and met or exceed them. Dont skimp on maintenance or bigger repairs could come.

The fluid that came in the system was dot 3. The manual calls for dot 3 or dot 4. I guess what I am asking is: Is it possible to exceed the specifications too much? Seeing as dot 5.1 is a step above what the manual even mentions - Could it harm my brake system in any way?

 

[ScottB]

If memory serves 5.1 is for racing applications and isnt as durable even though synthetic and requires replacing more often it also isnt compatible with previous fluids (must totally flush system) and does not like moisture. The others are more forgiving and thus why suggested in most automotive settings.

Heres something I googled for Wikepedia :

DOT 5 is silicone fluid and the above does not apply. Ideally, silicone fluid should be used only to fill non-ABS systems that have not been previously filled with glycol based fluid. Any system that has used glycol based fluid will contain moisture, glycol fluid disperses the moisture throughout the system and contains corrosion inhibitors. Silicone fluid does not allow moisture to enter the system, but does not disperse any that is already there either. A system filled from dry with silicone fluid, does not require the fluid to be changed at intervals, only when the system has been disturbed for a component repair or renewal. The United States armed forces have standardised on silicone brake fluid since the 1990s.

here too:

HowStuffWorks "What are the different types of brake fluid?"

 

[mbkite]

yes dot 5 is not for you.I believe its a silicone base brake fluid.
and will not perform as good as dot 3 or 4 silicone boils faster then regular brake fluid.so street driving is out with silicone.
I was told this when i was a mercedes benz mechanic. that was 10 years ago so things might have changed.. I would use dot 4.

 

[Christopher]

yes dot 5 is not for you.I believe its a silicone base brake fluid.
and will not perform as good as dot 3 or 4 silicone boils faster then regular brake fluid.so street driving is out with silicone.
I was told this when i was a mercedes benz mechanic. that was 10 years ago so things might have changed.. I would use dot 4.

I understand that I cannot use dot 5 - but isn't dot 5.1 different? Correct me if I am wrong, but dot 5 is silicone, while dot 3, 4, and 5.1 are glycol based.
Seeing if the latter of the group are all glycol based - shouldn't they be compatible? Or is there another underlying reason...

 

[Harleyguy]

Without going in a long and detail reason why you should or not use Dot 5.1 .The easiest way to look at when you want to replace something on your car is simple.Use what the original manufacturer used when they built the car.Dot 4 will work fine don't use a silicone based one different brake fluids are made to work in different type brake lines and also how well they absorb moisture.Go with Dot 4 it worked for you so far and will continue to work.

 

[Christopher]

Without going in a long and detail reason why you should or not use Dot 5.1 .The easiest way to look at when you want to replace something on your car is simple.Use what the original manufacturer used when they built the car.Dot 4 will work fine don't use a silicone based one different brake fluids are made to work in different type brake lines and also how well they absorb moisture.Go with Dot 4 it worked for you so far and will continue to work.

'Makes sense. Basically just stick with what the manufacturer recommends because the brake system may not be able to handle the chemical composition of a different fluid. Correct?

 

[Harleyguy]

'Makes sense. Basically just stick with what the manufacturer recommends because the brake system may not be able to handle the chemical composition of a different fluid. Correct?

You got it .Alot of people always want to redesign something that the car maker spent millions on to design.It's fine if you were running a 200 MPH race car or something along that line.It's the same when it comes to Gasoline you don't have to use a higher octane if the car passed EPA testing with a lower octane.Look in the owners manual if they say use 87 octane there is no reason to spend the money on 93 octane your not going to gain anything.

 

[Christopher]

You got it .Alot of people always want to redesign something that the car maker spent millions on to design.It's fine if you were running a 200 MPH race car or something along that line.It's the same when it comes to Gasoline you don't have to use a higher octane if the car passed EPA testing with a lower octane.Look in the owners manual if they say use 87 octane there is no reason to spend the money on 93 octane your not going to gain anything.

:thankyousign: